/* 基础样式 */
body {
    font-family: Arial, sans-serif;
    line-height: 1.6;
    margin: 0;
    padding: 0;
    background-color: #f4f4f4;
    color: #333;
}

header {
    background: #333;
    color: #fff;
    padding: 1rem 0;
    text-align: center;
}

nav {
    background: #444;
    color: #fff;
    padding: 0.5rem 0;
}

nav ul {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    justify-content: center;
}

nav ul li {
    margin: 0 1rem;
}

nav ul li a {
    color: #fff;
    text-decoration: none;
}

nav ul li a:hover {
    text-decoration: underline;
}

main {
    padding: 2rem;
}

section {
    margin-bottom: 2rem;
}

section h2 {
    margin-bottom: 0.5rem;
}

section p {
    margin-bottom: 1rem;
}

section ul {
    list-style: disc;
    padding-left: 20px;
}

section article {
    margin-bottom: 1rem;
}

section article h3 {
    margin-bottom: 0.5rem;
}

footer {
    background: #333;
    color: #fff;
    text-align: center;
    padding: 1rem 0;
    position: fixed;
    width: 100%;
    bottom: 0;
}